The present invention has its genesis in the field of mattress construction. In general, mattresses have an innerspring assembly composed of a plurality of coil springs which are arranged in a pattern within a border wire framework, with the coils and framework joined together in an intergral whole. Typically, multiple layers of insulative and other sheet material overlie the innerspring assembly, culminating in an outer covering layer of soft fabric.
One objective in designing a mattress is to optimize the distribution of pressure over the human body in a "deformed" profile, e.g., sleep position, while also providing satisfactory firmness. This objective has been quantified in one instance as an "idealized support profile" or model.
Measuring whether a mattress matches such an idealized model, or for that matter, matches whatever contour or shape is ultimately desired for the mattress when under load by a human being, has been a relatively inexact science to date. For example, one known way to measure the shape or contour of the mattress is to test it under load at various discrete points, typically along a line extending parallel to the longitudinal axis of the mattress. These individual data points can then be plotted to give an indication of the mattress "firmness" along that line. This method of measuring mattress contour is deficient in that the information obtained is only of a relatively small discrete area under load, and does not reflect shape or contour of the mattress under a wide area load, such as the human body. The measurement also takes an undesirable length of time to obtain, in light of the fact that a plurality of point measurements must be taken, typically one at a time.
Another known way of obtaining an indication of "feel" of a mattress is to have a group of individuals lie on the mattress surface one after another, and then compile their various verbal impressions of how the mattress "felt." While this "measurement" of the shape and surface of a mattress is plainly related to the configuration of the mattress under the wide area load of the human body, it obviously lacks objective detail, consistency and repeatability.